Screening apparatus



Sept. 11, 1928.

F. W. BRACKETT SCREENING APPARATUS Filed May l, 1926 3 Sheets-Sheet 1 septn 11, 192s. 145134,305

F. W. BRACKETT SCREENING APPARATUS Filed Play 1, 1926 3 Sheets-Sheet 2 #www .M

x septw 11, 1928. 1,684,305

F. W. BRACKETT SCREENING APPARATU S @www Patented Sept. 11, 1928i.

Unirse STATES FRANCIS WHITWELL BRACKETT, F COLCHESTER, ENGLAND.

SCREENING APPARATUS.

Application sied May 1, 192e, seriai No. 106,055,l and in Great Britain December as, 1925.

This invention relates to an improvement in or a inoditication ot that described in U. S.

Patent No. 1,585,461,7dated May 18, 1926.

The invention described in tliatspecication relates to improvements in screening apparatus ot' the kind in which the screen is an endless band made up ot a continuous rope, or its equivalent, 'travelling over drums in such a manner that it forms .parallel i0 lengths close enough to each other to itorm a screening surface.

The present invention relates to further improvements having for their object the prevention of clogging of the screen. l

According to said patent a. roller is grooved correspondingly with the lower drum and adapted to rotate in close proximity with this drum so as tov keepV the rope in the grooves of the drum. y

It has been found that in the event of a mass of material collecting on any ot the descending stretches of wire constituting the screen, this mass is liable to wedge itself bey tween the wire and the roller.

.grooved pulleys.

Another method oi avoiding trouble due to this wedging action consists in mounting the sli-ait of the rollerv iieXibly in self-aligning bearings, so that pressure between the wire and the roller causes the latter to move away from the wire thus allowing the mass of material to pass. A

Amprovement consists of grooves A further i in the guide roller, between the previously existing grooves in which the wire runs and .deeper than the latter grooves. l/Vhen the roller Vis made up of separate pulleys, t-he latter are so shaped that the deepr groove is formed when ytwo pulleys are contiguous.y

Since material, particularly of'a fibrous nature, tends to place itselil with its longest dij inensions longitudinally oil the roller, it ,ex-

tends across the said deep grooves and hasv through suitablegear, such as a chain, so

that ldependence is not placed on the wirek as a driving agent.

According to this invention the ill-effect or this,wedging` action'is diminished by con-` structing theV guide roller ot independent the bell-crank lever.

Furthermore, by providing a combA thas been found that one or more positively driven guide rollers for the ascending stretches .of wire help to prevent clogging of the screen and when such rollers are used it becomes convenient to drive the lower drum and also the several guide rollers by means of a chain drive roin the upper drum. Since matte-r is /liable to be dislodged i'rom the screenat the places where the wires are on 'the guide rollers, it is preferable to provide devices for preventing this dislodged-matter trom sliding back on thev screen; an example ot a suitable devicewill be described hereinatte i A further improvement is designed to remove matter, particularly of a fibrous nature, which clings tozthe wire that ascends to form the bight for the tensioning weight as described iii theaftoresaid patent. For this purpose revolving brushes 'driven from the shaft that drives the upper drum are used as vwill presently be explained. i

In the accompanying drawings, Fig. l is a side elevation ot a screen having the improveinents according to this invention; FiO'. 2 is a part end elevation; Fig. 3 is a section on line-S ot Fig'; Figs.'47 are drawn to. an enlarged scale, Fig. 4 being a p'artaxial section through a guide roller; F ig.r 5 a longitudinal section through the lower part of the screein-Fig. 6 a section on linegG-' of Fig. 5 and p v Fig. 7 a section through a detail.

The guidev roller a whichlreeps the wires' in the grooves oi" the lower drum Z) is preferably constituted of aA number of pulleysv similar to the upper and lower drums described ingsaid Patent No. 1,585,461.' Whether so constituted or not,H it is mounted to turn in spherical bearings c .(Fig. 6), each of which is carried by one arm of abell-crank lever p CZ pivoted to the frame of the screen at e.

rlhe roller ismaintainedin engagement with the stretch of wire by springs f, leach of the v springs being in compression between a bracket g on theframe and the other arm of r-lhe guide rollers a, Z, m have deep grooves h between-the grooves in which the wire i runs, as shownin Fig. 4, where-,inthe guide roller is shown as consisting of vseparate pulleys having their peripheries so shaped as to form the said deep grooves. Y

Fig. 4 also illustrates a comb 7c entering the grooves L. In Fig. l such a comb isshown as mounted to turn in bearingsin the frame and as provided with a lever handle le by f which it may be so turned, in close proximity to each of the drums, to the guide roller a and also to thel further guide rollers AZ' and* mf presently to be described. By turning handle lo periodically the'teeth of the comb can be caused to enter the grooves, as indicated in Fig. 4;," of the guideroller and' between the stretches of wire on the drum. In those cases shaft rotates, for the pur ose of preventing where the combs are beneath the'water level there are providedsuitably guided' rods k2, le*

connected with the handles lc" so that the latter can be-manipulated from above the water level.

The guide rollers Zand m are constructed similarl to' roller a but are mounted' in ordinary earings in the frame. Each oftheV guide'rollers'a, Zf and' m carriesa chain wheell 'nj and' the shafts' of the upper and lower drums al'so-carry'chain Wheels n. ll these cha-in wheels"` are in the same plane and are t driven'by the saine chain n2;

The rollers Z and m drive, through suitable gear of, shafts p mounted transversely in bearings on the frame and: carryingrubber flaps Q (Fig. 7) adapted to wipev the screen as the material dislodged from t ie screen from slidin'g back into the sump, as already referred to."

The screen is shown as formed oftwo wires,

asin that described in the said'pateiit, so that y there are two wires/z ascending to form tensioninr bivht's as shown in Fi 2. The arrangement for cleaning the-wires at' this placecomprises a frame r having lugs s adapted' te enter between flanges of the uprights t where' theyY can he adj ustlably iXed so that the angle whichV frame r makswith u rights canl be varied. In the framer are Journalled' twobrushes u geared together by wheels-v of different diameter, one of which is driven y through a universal joint by shaft w, itself ldriven through a universal joint ,from the counterhslhaft'` au of the main drive `through gear y. Y p

The two brushes u attacking the Wires at p Vdifferent speeds, have a thorough :leaningf' said invention andthe bestL means I known" "action, and their angular adjustability perl mits different portions of the brushes to be brought into action to compensate `for Wear.`

Having thus described the Vnature ofthe of carrying the same tinto practical elfect, I

l'. A screen ofthe kind described com1iris--v ing a lower grooved drum, an upper grooved drum, aV continuous rope wound 1n the grooves of the two drums and at least one guide roller having peripheral grooves alternately of dif-` ferent depth and of which the shallow grooves are each adapted to engage a length ofthe .said rope.,

ing an upper greeted drum and a lower groovedv drum, a contlnuous ro "e' woundiintllc i grooves of the twodrnis, a rine' in which the saidV drums are mounted', bearingsin the' frame near one of said d'rums a' c'ornb zn'eunt- Y ed to tarn in the said Bearings andmeimsffor rock-ing the comb to causeV its teeth to entel" between the s't'retclie'sof the said rope: Y

4; A screen of the kind deseribedcompris;

ing a lower grooved diem, anr upper groovedf grooved pulleys mounted to turn A having peripheral gro` iveso`fu which alternate grooves are shallower than the* remaining' grooves and each adapted to englageaA stretcl of the said rope, a frame i'nw "ich the said drums and rollerare mountedfbearngsin' the rocking the said comb to movfeits teeth info the deeper grooves of Said guide l'o'lllerl 5. A screen ofthe kindd'escrihed com rising an upper groove'd drum, means for riving said drum, a lower grooved'v drum, a tinuousy rope Wound' in the grooves ofthe druins,at least one guide roller fof'the ascendino ing'stretches of the sai'drop'e, earing'lor driving both the lower drum an 1 the' guide roller from the upper diiur'n, a-s'h'a'ffIo'nte'd above the guide roller,means'fordivin'gtlie said shaft from the 'guide roller adlap's carrisa by the gaia Shaft and; adapted' to wipe the ascending stretches of' the said rope.

6'. A screen of the l'nd described cofnpising a frame, an upper greov'ed" and a lowergrooved drum mountedin the frame,

.i a continuous rope wound'in' the grooves ofthe' two drumsandof lengtli-lgreater'th'an is nec-j essary to fill all the groovesfa vertical' frame erected on the aforesai'dframe, gaifegpu'lreys carried by the `said vertical frame and egag-V ing said rope to causethe excess length of roje to ascend substantially vertically and` to" epend as a high-t; and revolving brushes adapted to brush saidexcess length ofrope. t'

'In testimony whereof have signedf'ry' nameito this specification.

FRANCIS wmrwnrr sellers-Tr. 

